New technique reduces nicotine, harmful compounds in tobacco

RALEIGH, N.C. — Humans have indulged in tobacco for hundreds if not thousands of years. In recent decades however, physicians have discovered how detrimental certain compounds in the plant are for a user’s health. Now, a new technique developed by scientists at North Carolina State University is reportedly capable of removing certain carcinogens and other harmful chemical compounds from the tobacco plant.

The new technique targets plant metabolisms and researchers are hopeful that their work may help improve the health benefits of a number of crops, not just tobacco.

“A number of techniques can be used to successfully reduce specific chemical compounds, or alkaloids, in plants such as tobacco, but research has shown that some of these techniques can increase other harmful chemical compounds while reducing the target compound,” says De-Yu Xie, professor of plant and microbial biology at NC State and the corresponding author of a paper describing the research, in a university release. “Our technology reduced a number of harmful compounds – including the addictive nicotine, the carcinogenic N-nitrosonornicotine (NNN), and other tobacco-specific nitrosamines (TSNAs) – simultaneously without detrimental effects to the plant.”

Re-engineering tobacco to be a healthier crop

This new technique utilizes two types of molecular tools to produce new regulation designs: transcription factors and regulatory elements.

Transcription factors are proteins capable of turning certain genes on or off by binding to regulatory elements. Regulatory elements are short, non-coding DNA fragments in charge of the transcription of nearby coding genes.

Prof. Xie and his team hypothesized that those two “tools” may be the key to designing new regulations for the engineering of new, modified plant traits. Study authors zeroed in on two transcription factors (PAP1 and TT8) of the Arabidopsis variety due to their tendency to regulate the biosynthesis of anthocyanins (classes of nutraceutical compounds with antioxidant properties).

Professor Xie theorized that PAP1 and TT8 may be capable of helping in the repression of various harmful chemical compound levels, such as nicotine.

“PAP1 regulates pigmentation, so tobacco plants with our overexpressed PAP1 genes are red,” Prof. Xie explains. “We screened plant DNAs and found that tobacco has PAP1- and TT8-favored regulatory elements near JAZ genes, which repress nicotine biosynthesis. We then proposed that these elements were appropriate tools for a test. In all, we found four JAZ genes activated in red tobacco plants with a designed PAP1 and TT8 cassette overexpressed.”

Researchers tested this theory by studying a group of tobacco plants in both a greenhouse and field setting. Across both environments, the molecular tools resulted in drops in harmful chemical compounds as well as nicotine. For instance, plants with overexpressed PAP1 and TT8 saw a reduction ranging anywhere from 63 to 79 percent in the carcinogen NNN. Overall, four carcinogens common to tobacco plants dropped significantly.

In conclusion, Prof. Xie is hopeful that this work will lead to healthier and more beneficial crops and foods.

The study is published in the Journal of Advanced Research.